Facsimile scanning system



NOV. 25 1941. w, FINCH 2,263,987

FACSIMILE SCANNING SYSTEM Original Filed June 26, 1937 Pig: 2

INVENTOR I mm 9.35% BY Q I ATTORNEY lng, in which:

- Patented Nov. 25, 1941 UNITED STATES PATENT OFFICE- a FACSIMILE Z Z AZiZING SYSTEM I I William G. H. Finch, Newtown, Conn. Original application June 26, 1937, Serial No.

1940, SerialNo. 335,413

2 Claims.

This invention relates tofacsimile systems and more particularly relates to novel apparatus for providing smooth scanning at the record sheet.

In a facsimile transmitter or receiver the record sheet is scanned line by line at a predetermined rate. In commercial-operation rate of scanning generally ranges between 50 and 100 lines a minute. The operation of the scanner is by means of a motor with gear-down mechanism between the motor and the scanner. It has been found that gearing arrangements for driving the scanner mechanism cannot satisfactorily provide smooth operation of the scanner, particularly scanners of start-stop type receivers. The vibrations set up in the drum due to the starting and stopping thereof, in conjunction with gearing rattle between the continuously rotating motor and the drum, cause striations to appear on the recorded picture. striations traceable to the actual gear arrangements appear as alternate dark and light parallel streaks transverse to the scanning direction.

I have found that by providing a mechanical filter arrangement at the scanner mechanism, striations due to the spurious vibrations in the scanning system are substantially eliminated; In a preferred form of my invention, I couple the scanner to a driving plate with a pin and provide a flexible connection between the pin and the driving plate. By properly -proportioning the elasticity of thefiexible connection and the rotative inertia of the scanner mechanism cooperating therewith, the scanner will be operated in a smooth manner and the vibrations causing striations on the record sheet will be practically system.

These and further objects of my present invention will become apparent in the followin description of preferred forms for carrying out my invention taken in connection with the draw- Figure 1 is a plan view of a facsimile recording unit embodying one form of my invention.

Divided and this application May 16,

Figure 2 corresponds to the view taken alon 2-2 of Figure 1.

Figure 3 is the cross-sectional view takenalong 3-3 of Figure 1 through the mechanical driving connection to the drum. 7

Figure 1 is a. plan view of a preferred form of a picture recorder in conjunction with which my invention is employed. It is .to be understood that different types of recording mechanisms may equally well be used with my invention. The illustrated facsimile recorder is of the general type described in my Patent No. 2,047,863, which issued on July 14, 1936, entitled Telecommunications system, and specifically of the form disclosed in my co-pending application Serial No. 84,426, filed June 10, 1936 entitled Telepicture scanning systems.

- The record sheet I0 is mounted upon a rotatable drum II by means of the sheet fastening members H. The rollers l3 are used to facilitate smooth mounting of sheet upon the drum. Drum H is removably mounted between the pointed spindle Id of the tailstock l5and a shaft located within the housing 16 which is coupled to the drive motor l1 energized by a local power source through connection leads l8.

The motor I1 is driven near the predetermined synchronous speed and synchronizing mechanism (not shown)- is used to maintain the drum II in exact phase and synchronous relation with' the corresponding transmitter drum by means of cyclic synchronizing signals. The drum H is preferably operated on the start-stop principle drum II by means of a feed-screw 2| rotated in a predetermined speed ratio with respect to the drum II by means of reduction gearing located within thehousing 22. The scanner carriage 20 is guided in the parallel tracks 2324 and is secured to the feed-screw 2| by operating the cam lever 25 in a manner fully disclosed in my patent and application referred to above. The

received facsimile signals are caused to produce a light beam 26 varying in accordance with the shading of the original picture being transmitted in order that the resulting picture traced upon The picture drum II is coupled to the drive plate 21 by means of a pin '23 attached to the left flange 30 of the drum I l. Figures 2 and 3 illustrate details of the mechanical filter coupling between the drive plate 21 and the drum ll. Pin 23 is preferably encased by a rubber layer 3| and is fitted between two parallel leaf spring members 32-32 set into a recess 28 in the drive plate 21.

The drive plate 21 is operated directly from the synchronizing clutch member (not shown) and is supported on the housing It by a roller bearing 33. A spindle 34 projects through the center of the drive plate 21 for properly supporting the drum II in its axis of rotation. The rotation of drive plate 21 applies a rotative torque directly to the pin 23 through the leaf spring members 32 to rotate drum II.

The flexibility of the springs 32 is properly proportioned in conjunction with the rotative mass or inertia of the drum II to smooth out the spurious vibrations thereof. I have found 2,263,987 the recording sheet I will correspond thereto.

32 and the rubber covering 3|. The flexibility inherent in the springs 32 andthe cylinder of rubber 3| acting co-jointly with the rotational mass of cylinder II has been found to practically eliminate the vibrational tendencies of the drum causing dark and light alternate striations on the record sheet thereby greatly enhancing the quality of the reproduction. Although I have illustrated preferred forms for carrying out my invention it is to be understood that modifications thereof are feasible and that a drum having a relatively large rotative inertia is preferable, and have illustrated a cylinder 35 of lead or other heavy material attached to the flange 30 to increase the inertia or mass of the normally hollow drum l I.

It is important to have the leaf springs 32 adjusted accurately tangent to the pin 23 at its outer rubber surface covering 31 as illustrated in Figure 2. I have provided a simple method for maintaining this adjustment by the tapered pin 33 set into a slot 31 in the drive plate 21 centrally between the spring members 32. The tapered pin is forced between thesides of the narrow slot 31 until the proper operation of the leaf springs 32 is attained. This separation corresponds to the tangential alignment of the springs accordingly I do not intend to be limited thereby slot of said'drive plate extending between said springs for adjusting the amount of separation of said springs and a pin attached to said driven means and arranged to coact with said leaf springs between the opposed surface portions thereof.

2. A mechanical filter arrangement between a driving means and driven means comprising a drive plate operable by said driving means, said drive plate containing two opposed springs, a tapered peg set in a slot of said drive plate extending between said springs for adjusting theamount of separation of said springs and a pin.

attached to said driven means and arranged to coact with and register between said opposed springs.

WILLIAM G. H. FINCH. 

